On Tue, 2021-02-02 at 20:04 +0000, Don.Brace@xxxxxxxxxxxxx wrote: > -----Original Message----- > From: John Garry [mailto:john.garry@xxxxxxxxxx] > Subject: Re: [PATCH] scsi: scsi_host_queue_ready: increase busy count > early > > > Confirmed my suspicions - it looks like the host is sent more > commands than it can handle. We would need many disks to see this > issue though, which you have. > > So for stable kernels, 6eb045e092ef is not in 5.4 . Next is 5.10, and > I suppose it could be simply fixed by setting .host_tagset in scsi > host template there. > > Thanks, > John > -- > Don: Even though this works for current kernels, what would chances > of this getting back-ported to 5.9 or even further? > > Otherwise the original patch smartpqi_fix_host_qdepth_limit would > correct this issue for older kernels. True. However this is 5.12 material, so we shouldn't be bothered by that here. For 5.5 up to 5.9, you need a workaround. But I'm unsure whether smartpqi_fix_host_qdepth_limit would be the solution. You could simply divide can_queue by nr_hw_queues, as suggested before, or even simpler, set nr_hw_queues = 1. How much performance would that cost you? Distribution kernels would be yet another issue, distros can backport host_tagset and get rid of the issue. Regards Martin
